It's become a near-nightly ritual for many property owners recently: wrapping delicate plants in fabric to protect them from an unusually cold winter.

Imagine trying to keep hundreds of plants safe from the chill.

Malephora lutea at Tucson Botanical Gardens

Michael Chamberland thinks about it lot about, as director of horticulture at the Tucson Botanical Gardens.

He keeps a close eye on weather forecasts, especially the overnight lows. And on the coldest nights, he and his staff wrap many delicate plants in fabric.

Some are kept near heat lamps. Others are so sensitive that they spend the entire winter in a greenhouse.

Despite their best efforts, they'll lose some of the plants. In fact, Chamberland says some mortality is planned for at the gardens. It allows them to replant with hardier, more cold-resistant species.

It will take Chamberland and his staff some time to see how many plants were affected by the recent bout of sub-freezing temperatures. He says many will not show cold damage until mid-spring, when new growth appears.